Wireless telephones, which include both cellular telephones and the higher frequency personal communication devices, are growing in numbers and also shrinking in size and weight. The growth in numbers is influenced by the convenience and the per call cost of wireless telephones with respect to pagers and wire line telephones or coin telephones for completing calls, especially when the user is away from home or office.
Currently, the billing system of the cellular network differs from that of the Public Switched Telephone (wireline) Network (PSTN). Unlike the PSTN network, subscribers in the cellular network can be charged not only on a per month basis for local calls, but also on a per call basis depending on the plan purchased. For example, a subscriber can choose a plan that allots a certain number of minutes of air time for a set fee before being charged for air time usage. The amount of air time usage is based not only on calls placed from the mobile terminal, but also on calls received by the mobile terminal.
The use of cellular telephones has increased dramatically over the last few years. Subscribers to cellular telephone service generally are billed for the time the telephone is in use. The cellular service providers as marketing tools employ novel or creative billing packages.
Often the billing packages include a combination of rates. For example, the service may offer unlimited free off-peak time, limited free off-peak, reduced rates for different times of the day, graduated rates based upon volume usage and so forth. It will be appreciated that regardless of the billing package employed, the telephone user has a keen interest in tracking the amount of time the telephone is in use, for obvious reasons.
Most cellular telephones have a simple built-in timer that indicates the duration of the last call or the total usage since the timer was last reset. These simple timers are of little utility to the user who wishes to track his or her monthly peak or off-peak usage. The user may want to track the total number of peak minutes used in a given billing period. With primitive timers, the user may receive an unexpectedly large bill at the end of the month.
The user also may want to track the remaining balance of free minutes. For example, the user may forego using the telephone at certain times of the day for fear of going over budget when, in reality, the user still has unused free or reduced rate time available in the billing period.
Most service plans include a set number of calling minutes at a monthly rate, with extra time available at a per-minute rate. But minutes are only part of the picture; there are other usage habits to consider. For example, will you make most of your calls during or after business hours? Most plans differentiate “peak” and “off-peak” minutes, and may offer a generous number of off-peak minutes (evenings and/or weekends) as part of your monthly fee, or at a substantial discount. One-price calling plans that don't restrict usage times or minutes are becoming popular with heavy users. You usually can't carry over unused minutes from one month to the next, which inflates the per-minute cost of the calling time you do use.
Also known is a rollover program. If you have package minutes left over at the end of the month, they roll over to next month's minutes. In one known program the minutes expire after a year, and the program doesn't apply to night and weekend minutes.
Although most handsets can keep a running count of minutes used, they can't differentiate between peak and off-peak periods. Also, “Evening” and “weekend” may mean different things to different carriers (and even plans from the same carrier). The carriers aren't always helpful when it comes to tracking minutes. Sometimes the information can be as much as a day old. If you roam off your carrier's network, those fees might take a month or two to catch up with you.
As a result of these different known plans, many times a subscriber at the end of a billing cycle may have unused minutes of different amounts in different categories (such as peak minutes and off-peak minutes). Typically, these minutes are lost to the subscriber at the end of a billing cycle. It is a drawback of the prior art that a subscriber is not able to trade some or all of the minutes in a one category of usage for the same or a different number of minutes in a different category.
Therefore, there is a need in the prior art for a subscriber to be able to initiate a trade of, for example, off-peak minutes for peak minutes using their telecommunication network.